Reuters: Merging separate fights against air pollution and climate change could save cash and encourage developing nations such as China to do more to curb global warming, researchers said Wednesday. “There are big gains to be made” from a combined policy, said Petter Tollefsen, a researcher at the Center for International Climate and Environmental Research, Oslo (CICERO). The European Union alone could make efficiency gains of 2.8 billion euros ($3.62 billion) a year by 2020 by …